Evaluation and preservation solution

ABSTRACT

An evaluation and preservation solution for human and animal organs, tissues and parts thereof is described, wherein it comprises serum albumin at a concentration of 55-105 g/L, a scavenger and coating compound, preferably dextran compounds and derivatives thereof having essentially the same structure at a concentration of 1-55 g/L weight, and a physiological serum concentration of salts and nutrients in a physiologically acceptable medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/889,460, filed Aug. 13, 2007, now U.S. Pat. No. 8,012,677, which is acontinuation of U.S. application Ser. No. 10/415,740, filed Sep. 3,2003, now U.S. Pat. No. 7,255,983, which was the National Stage ofInternational Application No. PCT/SE2001/02419, filed Nov. 5, 2001,which claims the benefit of U.S. Provisional Application No. 60/279,725,filed Mar. 30, 2001. This application also claims foreign priority fromSwedish Application No. 0004032-9, filed Nov. 3, 2000. Each of theabove-listed applications is incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to an evaluation and preservation solutionfor human and animal organs and tissues and parts thereof fortransplantation, to a method for evaluation of such organs and tissuesand parts thereof before transplantation, and to a method fortransplantation from a non-heart-beating donor.

BACKGROUND ART

In clinical organ transplantation today kidneys, livers, hearts andlungs are the common transplanted organs. Pancreas is still not veryoften transplanted, and transplantation of small bowels and other organsare at the experimental stage. Regarding the preservation of kidneys,livers, hearts and lungs, the golden standard is cold ischemicpreservation. This means that the organ which is to be preserved isflushed with a cold preservation solution and after that the organ isimmersed in the same cold solution until it can be transplanted. Themost common organ preservation solution used today is the University ofWisconsin solution (UW). For the preservation of kidneys and livers UWis the most frequently used preservation solution. Even for hearts it isused more and more, but for hearts St Thomas solution in differentmodifications is still the most common solution. A new solution used inheart preservation in the last few years is Celsior, which is a solutionvery similar to UW, except that the potassium concentration is muchlower. For lungs Euro-Collins solution is still the most frequently usedsolution, but Perfadex is used increasingly. What all these solutionshave in common is that initially stated, i.e. that the organs areflushed with a cold solution and after that immersed in the same coldsolution. For kidneys and livers good preservation for up to 24 hours isobtained clinically, for lungs most trans-plant surgeons accept 6 hoursand for hearts 4 hours of cold ischemic time. The organs to betransplanted have hitherto been obtained from so called brain-dead butheart-beating donors or from non-heart-beating persons within minutesafter death, where the possibilities for acute harvesting and permissionfrom next of kin to do it happened to be present; such cases are rare,and will not solve the donor organ shortage. This is also accepted forlivers and kidneys. However, if organ donation from non-heart-beatingdonors will be a controlled clinical procedure, there is a need for anevaluation/preservation solution for organs from non-heart-beatingdonors, but so far no satisfactory solutions for this purpose have beenproduced. If this problem of lack of a convenient solution of this typecould be solved, a larger number of organs would be available fortransplantation, and the problem of lacking organs could besubstantially eliminated. At the moment, thousands of people world-wideare dying or suffering while waiting for organs for transplantation.None of the solutions in use at present for cold ischemic preservationcould be used as evaluation solutions for organs from anon-heart-beating donor. University of Wisconsin solution andEuro-Collins solution have an intracellular potassium content, whichgives vascular spasm at normothermia, and the same will St Thomas andCelsior do, although not to the same degree. Perfadex, which is a lowpotassium-dextran solution and could be used if mixed with erythrocytes,has not the oncotic pressure necessary for perfusing, e.g. lungs withoutoedema development.

OBJECT OF THE INVENTION

The object of the present invention is to solve the above-mentionedproblem of lack of a solution which makes evaluation and preservation ofhuman and animal organs, tissues and parts thereof for transplantation,particularly from non-heart-beating donors, possible.

This object is achieved by a combined evaluation and preservationsolution which is of the type mentioned by way of introduction and whichis defined in the characterising part of the independent claim.Preferred embodiments of the present invention are defined in thedependent claims.

The present invention also relates to a mixed solution ready for usecomprising the evaluation and preservation solution and red blood cells.

The present invention also relates to a method for the evaluation ofhuman and animal organs, tissues and parts thereof beforetransplantation and to a method for transplantation from anon-heart-beating donor.

The present invention also relates to use of the above-mentionedevaluation and preservation solution for the evaluation and preservationof organs, tissues and parts thereof before transplantation.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematically a lung perfusion test with an evaluation andpreservation solution, which in connection with the test and drawings iscalled evaluation solution for short, lacking both Dextran 40 and serumalbumin, as a function of the weight gain (expressed in kg) of the lungand time.

FIG. 2 shows schematically a lung perfusion test with an evaluationsolution with 50 g/L Dextran 40, but without human serum albumin, as afunction of the weight gain (expressed in kg) of the lung and time.

FIG. 3 shows schematically a lung perfusion test with an evaluationsolution with 70 g/L of human serum albumin but without Dextran 40 as afunction of the weight gain (expressed in kg) of the lung and time.

FIG. 4 shows schematically a lung perfusion test with an evaluationsolution containing 35 g/L of human serum albumin and 25 g/L of Dextran40 as a function of the weight gain (expressed in kg) of the lung andtime.

FIG. 5 shows schematically a lung perfusion test with an evaluationsolution containing 70 g/L of human serum albumin and 5 g/L of Dextran40 as a function of the weight gain (expressed in kg) of the lung andtime.

SUMMARY OF THE INVENTION

After extensive studies and experiments, the inventor has concluded thatto be able to perfuse organs from a non-heart-beating donor and evaluatethem at normothermia, the solution used must have a physiologicaloncotic pressure. Otherwise oedema will develop. The buffers andelectrolyte concentration in such a solution has to be similar to thosein plasma and be compatible with red blood cells. (Perfusion at 37° C.without oxygenated red blood cells would destroy the organ due to warmischemia). Further, the solution should also contain compounds openingup the capillary microcirculation. Further, the inventor has realisedthat the presence of a compound coating the endothelium, scavengingundesired substances and having detoxifying activity is required.Another requirement is that the solution after the organ or tissueperfusion/evaluation step is able to act as a satisfactory preservationsolution, so that it can be used for cold ischemic storage after theevaluation, if that would be the most practical way to transport theorgan to the receiver.

The evaluation and preservation solution for human and animal organs,tissues and parts thereof comprises serum albumin at a concentration of55-105 g/L, a scavenger and coating compound, preferably dextranmolecules and derivatives thereof at a concentration of about 1-55 g/L,together with physiological serum concentrations of salts and nutrientsin a physiologically acceptable medium. Preferably, the evaluation andpreservation solution according to the present invention comprises 65-85g/L, most preferably about 75 g/L, of human serum albumin.

Preferably, the evaluation and preservation solution according to thepresent invention comprises a dextran compound in a concentration of2-20 g/L, most preferably 5 g/L, and Dextran 40 is most preferred. Otherexamples of commercially available useful dextran molecules are Dextran60 and Dextran 70.

The salts contained in the solution according to the present, inventioncomprise sodium, potassium, calcium, magnesium, phosphate, hydrogencarbonate, and chloride ions, and the nutrients comprise physiologicallyacceptable carbohydrates, preferably glucose; fatty acids, e.g.essential fatty acids, and amino acids, e.g. essential amino acids. Thesolution according to the present invention may also contain avasodilator, preferably papaverin; antibiotics; fibrinolytic components,such as Actilyse, also called “altepas” (human tissue plasminogenactivator), and thrombocyte receptor blockers, such as Reopro, alsocalled “abciximab”. For long-term perfusion the solution according tothe present invention may contain hormones, e.g. tyroxin/triiodotyronin,insulin, cortison, growth hormone, and anabolic steroids, inphysiological concentrations.

Red blood cells in a serum solution are added separately to and mixedwith the above described solution according to the present inventionjust before the perfusion step. This mixed solution, also referred to as“artificial serum solution”, based on the evaluation and preservationsolution according to the present invention and the red blood cellcontaining solution is to be perfused into the organ, tissue or partthereof to be evaluated and represents one embodiment of the presentinvention, in the following referred to as “mixed solution ready for useaccording to the present invention” or, shortly, “solution ready foruse”.

The concentration of the ingredients present in the evaluation andpreservation solution according to the present invention is expressed ing/L of the solution to be mixed with the serum solution containing redblood cells. The concentration of the ingredients present in the mixedsolution ready for use according to the present invention, i.e. thesolution to be directly applied to or to perfuse the organ, tissue orpart thereof to be evaluated and optionally preserved beforetransplantation, is expressed in g/L of the “artificial serum solution”.When mixing the evaluation and preservation solution according to thepresent invention with the serum solution containing red blood cells,the concentration of the ingredients of the original evaluation andpreservation solution is slightly reduced due to a small dilutioneffect, as appears from the concentration data presented in thefollowing. This dilution effect is generally about 8% and affects inprinciple only the higher values in the concentration intervalspresented.

The expression “organs, tissues and parts thereof” used throughout theapplication text means all parts of the body which can be transplantedat present and in the future.

The expression “non-heart-beating donor” used throughout the applicationtext means a patient for which the heart has been irreversibly arrestedand brain death has been assumed, i.e. a hands off period of minimum 1.0minutes at normothermia after the diagnosis of irreversible heartarrest.

The expression “serum albumin” used throughout the application textmeans albumin derived or purified from a human or animal serum source orrecombinant serum albumin produced by genetic engineering. Anyderivatives and analogues thereof having essentially the same physicalaction in the present invention are also contemplated to be included inthis expression.

The expression “physiological serum concentration” used throughout thepresent application text means serum concentrations of the substances inquestion which exactly or essentially correspond to the normal serumconcentration in human and animal blood.

The term “lung(s)” used throughout the application text includes thewhole lung(s) including bronchi and also lobes and segments thereof.

Serum albumin is a water-soluble plasma protein. It is produced in theliver and is important for the oncotic pressure, also called thecolloidosmotic pressure, of the blood, i.e. it has the capability ofmaintaining the plasma of the blood within the vessels. It also act as atransport protein for many substances, e.g. fatty acids. The serumalbumin is negatively charged and is surrounded with sodium ions.Therefore, it is very difficult for the serum albumin to pass throughthe capillary wall. The oncotic pressure in the blood is normallymaintained at a level of 25 mm Hg. E.g. human serum albumin, having amolecular weight (Mw) of 69,000, is too large to pass out through thesemi-permeable capillary walls, and the concentration thereof isnormally about 45 g/L blood. As it is negatively charged, serum albuminattracts sodium ions, and this add about 7 mm Hg to the oncotic pressure(the so-called Donnan effect). The hydrostatic pressure in the arterialend of the capillaries is normally about 30 mm Hg, and the hydrostaticpressure in the venous end of the capillaries is normally about 10-15 mmHg. As stated above, an intermediate oncotic pressure of about 25 mm Hgexists in the capillaries, making water to leave in the arterial end andreturn in the venous end.

As the serum albumin is responsible for the maintenance of the correctoncotic pressure, it has an important function as a colloidosmoticallyactive substance, providing about 70% of the oncotic pressure. If asolution containing a satisfactory electrolyte composition mimicing thatin normal plasma, but without colloidosmotically active substances, itwould immediately create a weight gain due to oedema formation in theorgan to be transplanted. As normal human plasma also contains gammaglobulins and other protein molecules, providing about 30% of theoncotic pressure, the present inventor found that the solution accordingto the present invention should not only contain serum albumin, but alsoin an increased amount with a view to compensating for the oncoticpressure normally induced by the gamma globulins and other proteinmolecules, which are absent in the solution according to the presentinvention. In an aqueous test solution containing normal extra-cellularconcentrations of sodium, potassium, calcium, magnesium, chlorine,hydrogen carbonate, phosphate and glucose and having a normal osmolarityof about 290, different concentrations of human serum albumin have beentested on lungs. At a concentration of about 70 g/L in the solutionready for use, the best results were obtained, i.e. the lungs wereperfused without oedema formation. The oncotic pressure in this testsolution was about 25 mm Hg, i.e. corresponding to the oncotic pressurein normal lung capillaries. Satisfactory results can be obtained with aserum albumin concentration of 50-100 g/L in the solution ready for use,whereby an acceptable degree of slight oedema formation occurs in thelower end of the range. Better results are obtained with a serum albuminconcentration of about 60-80 g/L in the solution ready for use, butoptimal results are obtained with a concentration of 70 g/L, as statedabove. If increasing to higher than 70 g/L, a higher perfusion pressurecan be used without oedema formation. To achieve a perfusion flow fortesting the lungs for transplantation a perfusion pressure of at most 20mm Hg is necessary. Thus, with a view to avoiding substantial oedemaformation during such a perfusion, the oncotic pressure of the solutionhas to be at least 5 mm Hg higher than the hydrostatic pressure.

The evaluation and preservation solution according to the presentinvention also comprises a scavenger and coating compound, whichpreferably is chosen from the group comprising dextran molecules, e.g.the commercially available Dextran 40, Dextran 60 and Dextran 70, andderivatives thereof having essentially the same structure. Dextran 40 isthe most preferred scavenger and coating compound according to thepresent invention. Dextran molecules having other molecular weights,e.g. from as low as 1 and up to 250 kDa, more preferably from 20 and upto 150 kDa, could also be useful. However, when dextran of 1 kDa, i.e.Dextran 1, is used the concentration should be 10-140 g/L. Alternativesto Dextran 1 are lactobionate, raffinose, and mannitol, all having amolecular weight below 1 000 Da.

The scavenger and coating compound has several activities at the sametime, and it acts as a coating substance for the capillary endotheliumof the organ to be transplanted, as a scavenger of toxic and otherundesired substances and as a detoxifying agent. For simplicity reasons,this compound is called “scavenger and coating compound” in the presentapplication. Other compounds being scavenger and coating compoundsaccording to the definition herein could also be present in the solutionaccording to the present invention in combination with dextrancompounds. However, pure scavenger compounds, i.e. having no or minorcoating effect, also exist having a similar or better scavenging effectthan the dextran compounds per se, e.g. allopurinol, vitamin C, vitaminE, didox, trimidox. Thus, such a pure scavenger or combinations thereofmay be present in the solution in combination with the dextran compound,thereby obtaining an additive or synergistic effect. Further, compoundshaving only coating effects on the capillary endothelium, i.e. no orminor scavenging or detoxifying effect, may also be present in thesolution according to the present invention in combination with thedextran compound or the pure scavenger compound, thereby obtaining anadditive or synergistic effect.

Dextran compounds have turned out to be most efficient for the purposeof the present invention as they present all of the above-mentionednecessary activities. Dextran molecules are composed of glucose units ina long chain and are also provided with glucose side chains. Dextran 40has a molecular weight (Mw) of 40,000 Da, and correspondingly themolecular weight for Dextran 60 and 70 is 60,000 and 70,000 Da,respectively. The higher the molecular weight, the longer is the dextranmolecule.

The capillaries in the lungs have large pores with a diameter of about30 nm. Gamma globulins are small enough to pass through these pores witha view to entering the capillary interstitial space to attack microorganisms and then be transported away via the lymphatic system.

The dextran molecules are not electrically charged, and they have thecapability of passing through the large pores just like a worm, i.e. itis the diameter of the dextran molecule that is decisive of passage, notthe length and molecular weight thereof.

When evaluating an organ which has been exposed to warm ischemia, oedemaformation can be regarded as a reperfusion injury, which issubstantially reduced by use of a scavenger and coating compound,preferably dextran compounds, particularly Dextran 40, in the solutiondue to its capability of coating the capillary membranes. As a result,it will be difficult for leucocytes to stick to the capillaryendothelium and pass through the dextran molecule-coated capillaries.However, dextran molecules as such contribute partly to the oedemaformation when passing through the capillary membrane pores. Thus, thedextran molecule concentration has to be optimal, i.e. the concentrationshould not be so high that the oedema formation is harmful, but also notso low that the overall advantageous scavenging and coating effectbecomes insufficient.

Among several dextran concentrations tested for Dextran 40, aconcentration in the range of 1-50 g/L in the solution ready for use hasshown satisfactory results, particularly in the range of 2-20 g/L, andespecially at a concentration of 5 g/L. A 3 hour evaluation test of alung at the above-mentioned latter Dextran 40 concentration gave noweight gain of the lung, and as the evaluation and preservation solutionis recirculated in the lung, it contains enough Dextran 40 to achieveeffective coating of the capillary membrane. Transplanted lungs have,after evaluation and preservation with an evaluation and preservationsolution according to the present invention, shown that full effect isachieved with 5 g/L Dextran 40 in the solution ready for use. In thesetests a serum albumin concentration of 70 g/L was used.

As stated above, other dextran molecules are also effective, but theoptimal concentration is somewhat depending on the molecular weight of adextran molecule. However, the optimal concentration for e.g. Dextran 60and Dextran 70 is the same or essentially the same as for Dextran 40.

Further, another compound having a function similar to those of serumalbumin in this context is a particular hyaluronic acid based product,e.g. chemically modified, and variants thereof having essentially thesame structure as albumin. This hyaluronic acid based product has beenproduced by enzymatic degradation of native hyaluronic acid, followed bycontrolled aggregation of the fragments and modulation to a globularilyshaped product having a negative charge and a molecular weight of about69 kDa, i.e. a product having similar size, shape and charge as serumalbumin. The production of this chemically modified hyaluronic acidbased product is described in e.g. EP-B-0 556 213, WO 00/46253 and WO00/46252. This product can replace the serum albumin partially, oroptionally completely, in the solution according to the presentinvention, still giving the effect desired. However, due to the Donnaneffect discussed above the optimal concentration of the hyaluronic acidbased product may vary with ±15% in relation to the dextran moleculeconcentration in the solutions according to the present invention. Ifboth of these compounds are present in the solution at the same time,the sum of the concentrations thereof should not exceed 115 g/L.

The own blood from the dead human or animal from which the organ ortissue to be transplanted is donated would not be satisfactory as anevaluation and/or preservation solution. During experiments with pigsthe blood of the dead pig showed shortly after death toxic products.When this blood is pumped through oxygenators and pump systems in aheart-lung machine, the complement system is activated and other toxicproducts are produced, whereby a lung evaluation becomes impossible.

The same activation of the complement system occurs if plasma and redblood cells, although having the correct blood grouping, from a bloodbank are mixed into a solution. However, to achieve an effectiveevaluation red blood cells have to be added to the evaluation solution.Thus, a serum solution containing red blood cells is added as acomplement to the evaluation and preservation solution according to thepresent invention. Preferably, washed or purified, i.e. leucocytefiltered and radiated, red blood cells from a blood bank are used. Inthis context, blood collected from donors is deprived of plasma andplatelets. Conventionally, a CPD (citrate/phosphate/dextrose) solutionis added in such a way that the erythrocyte volume fraction (EVF), alsocalled the hematocrite value, for the red blood cells is 50%. In such aCPD solution the serum part constitutes about 78 ml and the red bloodcell fraction about 222 ml. Optimal evaluation results are obtained if300 ml of such a conventional CPD solution containing red blood cells isadded per one liter of the evaluation and preservation solutionaccording to the present invention as defined in claim 1. Thereby, dueto a slight dilution effect, in such a mixed solution ready for use andto be directly added to the organ, tissue or part thereof to beevaluated, the concentration of serum albumin is 50-100 g/L, preferably60-80 g/L, and most preferably 70 g/L. The concentration of thescavenger and coating compound in the case of dextran compounds is 1-50g/L, preferably 2-20 g/L, and most preferably 5 g/L in the solutionready for use. For ex vivo use during the evaluation step an EVF,defining the erythrocyte volume fraction, of 15±5 vol % is attained forthe mixed solution to perfuse with. The red blood cells are perfectlycompatible with said solution, and their oxygen uptake and carbondioxide emitting function is completely normal in this solution.Further, it should be noted that the conventional solution containingred blood cells should not be added to the solution according to thepresent invention more than about 30 minutes before the start of theperfusion due to stability problems.

Preferably, the physiologically acceptable medium comprised in thesolution according to the present invention is water.

It should also be noted that the oedema formation problem describedabove in connection with perfusion during lung evaluation isparticularly pronounced for lungs. The same problem arisescorrespondingly for other organs and tissues to be transplanted, but toa smaller extent.

In transplantation surgery of a non-heart-beating donor patient, e.g. aperson who has died in an acute heart arrest, the organ or tissue to betransplanted, e.g. a lung, has to be cooled when still present in thedead body within two hours, preferably one hour, from the death. Thelungs of the donor body can be cooled at a temperature of 8-12° C.without risk of injury the next 24 hours. To obtain this cooling oflungs, the pleura is initially perfused with a conventional solution forthis purpose, e.g. Perfadex solution.

Thereafter, the lung is harvested from the donor body and is placed in aheart-lung machine comprising a pump, an oxygen supply, an oxygenator,and a respirator. The lung is then filled with the mixed solution of theevaluation and preservation solution according to the present inventionand the serum solution containing red blood cells, having an EVF of 15±5vol %. Then the lung is evaluated with a view to deciding whether it isacceptable for transplantation, i.e. the blood gases, the vascularresistance, the endothelial function, the lung compliance, anyventilation/perfusion disorders, the gas output, and the surfactantfunction is evaluated. If acceptable, the lung is transplanted into thereceiver body and has all of its important physiological functions andactivities kept intact. This kind of lung, evaluation andtransplantation has never been done until now, i.e. a successfultransplantation of a lung from a non-heart-beating donor and evaluationin the way described above.

The evaluation and preservation solution according to the presentinvention also works for the evaluation of all organs and tissues of thehuman and animal body, in extreme also for the whole human or animalbody as such and also for all organs and tissues from traditionalbrain-dead but heart-beating donors of both human and animal origin, andgives also better results than all other corresponding solutions knownso far. It is useful for all organs in the preservation aspect except,the heart. If used to preserve the heart for cold ischemic storage, thepotassium concentration has to be raised to 16-30 mmol/l, preferably20-26 mmol/l, and most preferably 23 mmol/l. This general applicationfor all organs and tissues can be explained by the fact that as thesolution according the present invention is highly efficient for theevaluation of lungs, which are known to be most sensitive of all organsdue to the large capillary membrane pores, then it has to be effectiveon all other organs due to their smaller pores.

For heart evaluation, the potassium concentration in the solutionaccording to the present invention has to be increased from the normallevel of about 4.5 up to about 23, thereby achieving cardioplegia.

Non-exhaustive examples of organs and tissues of most interest to betransplanted and therefore first evaluated are lung(s), hearts, livers,kidneys, pancreas, small bowel, body extremities, etc.

The mixed solution ready for use according to the present inventionshould be run through a pump giving physiological perfusion pressure inthe organ to be transplanted. Further, the solution should pass throughan oxygenator to supply the red blood cells with oxygen and take up theCO₂. If plasma with red blood cells from a blood bank is used in aclosed circle with oxygenators and plastic tubes, the activation of thecomplement system, substances and other toxic systems precludes stableperfusion.

The solutions according to the present invention lacks toxic propertieswhen used in a closed evaluation system including oxygenators and pumps.In such way the organ to be transplanted can be perfused for 24 hours ormore, during which time no ischemia occurs. During tests hearts havebeen preserved with the mixed solution ready for use according to thepresent invention (with a potassium concentration of 23 mmol/l), whichhas been oxygenated by an oxygenator and pumped through the heart for 24hours, followed by transplantation of the heart, which showed perfectfunction from the very beginning. If the preservation and evaluationsolution according to the present invention is mixed with red bloodcells to an EVF of 15±5 vol %, lungs from non-heart-beating donors canbe evaluated and after the evaluation the lungs can be preserved for atleast 36 hours before transplantation by cold ischemic storage at 4° C.

Examples of two preferred evaluation and preservation solutionsaccording to the present invention are the following:

One preferred embodiment of the evaluation and preservation solutionaccording to the present invention consists of the following componentsin the concentrations shown.

Component Concentration Dextran 40 5 g/L Sodium chloride 98 mmol/LPotassium chloride 0.49 mmol/L Calcium chloride 1.4 mmol/L Magnesiumsulphate 1.2 mmol/L Potassium dihydrogen phosphate 0.042 mmol/LDipotassium hydrogen phosphate anhydrate 0.84 mmol/L Disodium hydrogenphosphate dihydrate 0.029 mmol/L Sodium bicarbonate 14 mmol/L Potassiumacetate 2.9 mmol/L Glucose monohydrate 10 mmol/L Albumin Centeon (200mg/ml) 64 g/L Sodium hydroxide (1M) Sterile water

The components are dissolved in sterile water and pH is adjusted to 7.4with sodium hydroxide.

Another preferred embodiment of the evaluation and preservation solutionaccording to the present invention consists of the following componentsin the concentrations shown.

Component Concentration Dextran 40 5 g/L Sodium chloride 86 mmol/LPotassium chloride 4.6 mmol/L Calcium chloride dihydrate 1.5 mmol/LSodium dihydrogen phosphate dihydrate 1.2 mmol/L Sodium bicarbonate 15mmol/L Magnesium dichloride hexahydrate 1.2 mmol/L D(+)-glucosemonohydrate 11 mmol/L Human serum albumin (200 g/l) 70 g/L Sodiumhydroxide (1M) Sterile water

The components are dissolved in sterile water and pH is adjusted to 7.4with sodium hydroxide. The mixed solution ready for use according to thepresent invention is obtained by mixing each of the both preferredembodiment solutions (1 000 ml) with 300 ml of the above described CPDsolution.

The most preferred evaluation and preservation solution according to thepresent invention for a heart is similar to that for lungs, but has ahigher potassium concentration, as defined above.

Experiments

A weight gain of the lung during the evaluation step beforetransplantation, is significant for undesired oedema formation, whichoccur when a test solution not containing the correct concentrations ofserum albumin is used.

Different experiments have been performed for evaluation solutionscontaining different components during the evaluation of a lung. Theweight gain (expressed in kg) was measured against time during aconstant perfusion flow rate.

A solution ready for use containing neither serum albumin, nor scavengerand coating compound gave a significant weight gain, showing theshortages of such a solution, as shown in FIG. 1.

A solution ready for use containing Dextran 40, but no human serumalbumin, gave an even more substantial weight gain by time, as shown inFIG. 2.

A solution ready for use containing 70 g/L human serum albumin, but noDextran 40, gave an unsatisfactory weight gain by time, as shown in FIG.3.

A solution ready for use containing 35 g/L of serum albumin and 25 g/Lof Dextran 40 gave an unsatisfactory weight gain by time. This weightgain depends on the too high concentration of Dextran D 40, i.e. 25 g/Land the too low concentration of albumin, i.e. 35 g/L.

A solution ready for use containing 70 g/L of serum albumin and 5 g/L ofDextran 40 gave no weight gain by time. This solution represents a mixedsolution ready for use according to the present invention, i.e. both theserum albumin and the Dextran 40 in correct concentrations.

The present invention also refers to a method for evaluating an organ ora tissue to be transplanted, wherein said organ or tissue is perfusedwith the evaluation and preservation solution according to the presentinvention mixed with the serum solution containing red blood cells,followed by evaluation of the organ or tissue, and optional preservationin the same solution until transplantation. For lungs the perfusion flowrate during the evaluation is about 4 liters/min, the temperature isabout 37° C. and the maximum perfusion pressure is about 20 mm Hg. Theperfusion flow rate is lower when perfusing other organs. For theevaluation of a kidney, the perfusion pressure must be as high as about90 mm Hg.

The present invention also refers to a method of transplantation of anorgan, tissue or a part thereof from a non-heart-beating human or animaldonor, in which the organ, tissue or part thereof is harvested from thedonor body, is perfused with the evaluation and preservation solutionaccording to the present invention mixed with the serum solutioncontaining red blood cells, the organ or tissue or part thereof isevaluated, and, if the organ, tissue or part thereof is acceptable fortransplantation, it is preserved in said solution until transplantation.Preferably, said organ is a lung.

It should also be noted that the evaluation and preservation solutionaccording to the present invention is applicable to all kinds oftransplantation, e.g. auto-, allo- and xenotransplantation.

The invention claimed is:
 1. A method of perfusing an organ, tissue, orpart thereof, of an animal or human, the method comprising: (1)evaluating the organ, tissue, or part thereof; and (2) perfusing theorgan, tissue, or part thereof at normothermia by recirculation with asolution; wherein the solution comprises: (a) a colloidosmoticallyactive substance that is too large to pass out through semipermeablecapillary walls of the animal or human and that is present at aconcentration that provides the oncotic pressure of serum albumin at aconcentration of 55-105 g/L; (b) a scavenger and coating compound, whichcoats the capillary endothelium of the organ, tissue, or parts thereof,at a concentration of 1-55 g/L; (c) a physiological serum concentrationof a salt; and (d) a nutrient for the organ, tissue, or part thereof, ina physiologically acceptable medium; and further wherein the evaluatingcomprises measuring evaluation parameters of the organ, tissue, or partthereof for transplantation thereof; the solution provides an oncoticpressure higher than an applied hydrostatic pressure in the organ,tissue, or part thereof, and prevents oedema formation; and the organ,tissue, or part thereof is connected to a heart-lung machine during theperfusion.
 2. The method of claim 1, wherein the organ is a lung, aheart, a kidney, a liver, a pancreas, or small bowels.
 3. The method ofclaim 1, further comprising preserving the organ, tissue or part thereofin said solution until the transplantation.
 4. The method of claim 1,wherein the organ is a lung.
 5. The method of claim 1, wherein theorgan, tissue, or part thereof is harvested from a non-heart-beatinganimal or human donor, and the evaluating further comprises evaluatingif the organ, tissue, or part thereof is acceptable for transplantation;and further comprising transplanting the organ, tissue, or part thereofinto a receiver body.
 6. The method of claim 5, further comprisingpreserving the organ, tissue, or part thereof in the solution until thetransplantation.
 7. The method of claim 5, wherein the organ, tissue, orpart thereof is auto-, allo- or xenotransplanted.
 8. The method of claim1, wherein the colloidosmotically active substance has a negative chargeand a molecular weight of about 69 kDa.
 9. The method of claim 1,wherein the colloidosmotically active substance is a hyaluronicacid-based compound having a molecular weight of about 69 kDa.
 10. Themethod of claim 1, wherein the colloidosmotically active substance ispresent in the solution at a concentration that provides the oncoticpressure of serum albumin at a concentration of 65-85 g/L.
 11. Themethod of claim 1, wherein the colloidosmotically active substance ispresent in the solution at a concentration that provides the oncoticpressure of serum albumin at a concentration of 70 g/L.
 12. The methodof claim 1, wherein the scavenger and coating compound has a molecularweight ranging from 1 to 250 kDa.
 13. The method of claim 1, wherein thescavenger and coating compound has a molecular weight ranging from 15 to115 kDa.
 14. The method of claim 1, wherein the scavenger and coatingcompound has a molecular weight ranging from 20 to 150 kDa.
 15. Themethod of claim 1, wherein the concentration of the scavenger andcoating compound in the solution is 2-20 g/L.
 16. The method of claim 1,wherein the concentration of the scavenger and coating compound in thesolution is 5 g/L.
 17. The method of claim 1, wherein the salt comprisesone or more of sodium, potassium, calcium, magnesium, phosphate,hydrogen carbonate, and chloride ions; and the nutrient comprises one ormore of a physiologically acceptable carbohydrate, fatty acid, and aminoacid.
 18. The method of claim 17, wherein the physiologically acceptablecarbohydrate is glucose.
 19. The method of claim 1, wherein the solutionfurther comprises at least one of the following: a vasodilator; anantibiotic; a fibrinolytic component; a thrombocyte receptor blocker; ahormone; an insulin; a cortisol; a growth hormone; and an anabolicsteroid.
 20. The method of claim 1, wherein the solution furthercomprises a pure scavenger compound.
 21. The method of claim 1, whereinthe solution further comprises papaverine, alteplase, abciximab,tyroxin/triiodotyronin, or a combination thereof.
 22. The method ofclaim 12, wherein the scavenger and coating compound is a dextrancompound.
 23. The method of claim 13, wherein the scavenger and coatingcompound is a dextran compound.
 24. The method of claim 14, wherein thescavenger and coating compound is a dextran compound.